In conference rooms or auditoria there is not only a need for tables at normal height, but also for table surfaces at lectern height. Taller table surfaces are required, for example, as a shelf surface to accommodate a script in the case of a lecture given in a standing position, as a surface for a projector, or also simply to enable something to be placed thereon so as to be readily visible. In addition, different table heights are required, as a rule, in the form of table surfaces adjacent the normal-height tables.
Swiss patent specification No. 225 533 discloses a flat desk which can be converted to a draftsman's desk, comprising a desk tabletop provided with hinged feet. The latter are articulated to the desk tabletop at one end and to a top part of the flat desk at the other end. The desk tabletop is raised in the rear region by unfolding the feet. To place the desk tabletop in a horizontal position two hinged transverse supports are provided. It has a disadvantage that a gap forms between the raised tabletop part and an adjacent stationary tabletop, and articles on the table can fall into this gap. Also, the raised tabletop can only be aligned horizontally at the height determined by the transverse supports and pivotable feet. Another disadvantage is that the tabletop is not continuously adjustable as to height.
WO 90/03133 discloses a table construction wherein a tabletop is divided into two by a joint, the first part being articulated on the support frame and the second part being articulated on the first part and hence being adjustable as to height with the pivoting of said first tabletop part. A lever parallelogram consisting of the two tabletop parts, the support frame, and a lever parallel to the pivotable tabletop part can be secured in different positions by a locking device.
A disadvantage of both these tables is that in each case only the height-adjustable part remains horizontal while the remaining tabletop surface is inclined. It is, therefore, impossible to have articles lying on one part of the table surface while another part is adjusted as to height. No adjacent shelf surfaces with different table heights can be obtained with such a table.